Skip DetachVolume if volume is not attached

builtin/providers/aws/resource_aws_volume_attachment.go

@@ -153,6 +153,20 @@ func resourceAwsVolumeAttachmentDelete(d *schema.ResourceData, meta interface{})
 	vID := d.Get("volume_id").(string)
 	iID := d.Get("instance_id").(string)
 
+	desc_opts := &ec2.DescribeVolumesInput{
+		VolumeIds: []*string{aws.String(vID)},
+	}
+
+	attr, desc_err := conn.DescribeVolumes(desc_opts)
+	if desc_err != nil {
+		return fmt.Errorf("Error reading EC2 volume %s: %s", vID, desc_err)
+	}
+
+	if *attr.Volumes[0].State == "available" {
+		d.SetId("")
+		return nil
+	}
+
 	opts := &ec2.DetachVolumeInput{
 		Device:     aws.String(d.Get("device_name").(string)),
 		InstanceId: aws.String(iID),